diff --git a/docs/content/doc/usage/errors.md b/docs/content/doc/usage/errors.md
index e0c05faa0..b33b550a0 100644
--- a/docs/content/doc/usage/errors.md
+++ b/docs/content/doc/usage/errors.md
@@ -90,6 +90,7 @@ This document describes the different errors Vikunja can return.
 | 4019 | 400 | Invalid task filter value. |
 | 4020 | 400 | The provided attachment does not belong to that task. |
 | 4021 | 400 | This user is already assigned to that task. |
+| 4022 | 400 | The task has a relative reminder which does not specify relative to what. |
 
 ## Namespace
 
diff --git a/pkg/models/error.go b/pkg/models/error.go
index 694ef0f3a..69b63cedd 100644
--- a/pkg/models/error.go
+++ b/pkg/models/error.go
@@ -898,7 +898,7 @@ func (err ErrReminderRelativeToMissing) HTTPError() web.HTTPError {
 	return web.HTTPError{
 		HTTPCode: http.StatusBadRequest,
 		Code:     ErrCodeReminderRelativeToMissing,
-		Message:  "Relative reminder without relative_to",
+		Message:  "Please provide what the reminder date is relative to",
 	}
 }
 
diff --git a/pkg/modules/migration/vikunja-file/vikunja.go b/pkg/modules/migration/vikunja-file/vikunja.go
index 3e4c6011d..851b9e74a 100644
--- a/pkg/modules/migration/vikunja-file/vikunja.go
+++ b/pkg/modules/migration/vikunja-file/vikunja.go
@@ -141,7 +141,12 @@ func (v *FileMigrator) Migrate(user *user.User, file io.ReaderAt, size int64) er
 					comment.ID = 0
 				}
 				for _, attachment := range t.Attachments {
-					af, err := storedFiles[attachment.File.ID].Open()
+					attachmentFile, exists := storedFiles[attachment.File.ID]
+					if !exists {
+						log.Debugf(logPrefix+"Could not find attachment file %d for attachment %d", attachment.File.ID, attachment.ID)
+						continue
+					}
+					af, err := attachmentFile.Open()
 					if err != nil {
 						return fmt.Errorf("could not open attachment %d for reading: %w", attachment.ID, err)
 					}